This invention relates to a method for rapid identification of Bacillus cereus and the kit thereof.
Bacillis cereus is gram-positive, spore-forming, motile, aerobic rod which inhibits in soil and has been recognized as an opportunistic food poisoning pathogen. Bacillis cereus and the poison thereof usually result in the diarrheal syndrome and the emetic syndrome. Some food types that are preferentially contaminated with B. cereus are crude cereals, starchy foods, dairy products, meat, dehydrated foods, and spices.
Conventional procedures for the detection of B. cereus are based on morphologic observations, physiological and biological tests, such as plate count method and most probable number method. Harmon et al. utilized the hydrolysis of lecithin (egg yolk reaction) as a characteristic for isolation of suspect B. cereus on selection media such as mannitol-egg yolk-polymyxin (MYP) agar. However, it should take several days to complete the physiological and biological tests. (Harmon, S. M. et al., 1992, Compendium of methods for the Microbiological examination of foods. 3rd ed. American Public Health Association, Washington, D.C., pages 593-604) Schraft et al. developed polymerase chain reaction for detection of lecithin-hydrolyzing gene of B. cereus. Since most strains of the B. cereus group (i.e., B. cereus, B. mycoides and B. thuringiensis) possess lecithinase activity, the polymerase chain reaction method detects all species of the B. cereus group, but does not distinguish any single species. (Schraft, H. and M. W. Griffiths, 1995, Sepecific oligonucleotide primers for detection of lecithinase-positive Bacillus spp. by PCR. Appl. Environ. Microbiol. 61: 98-102). Thus, a rapid and specific method for identification of B. cereus is desired.
The objective of this invention relates to provide a method for rapid identification of Bacillus cereus in a sample comprising
(a) mixing an antibody or antisera specifically against the cell surface antigens of B. cereus with the sample, wherein the surface antigen is selected from the group of consisting of: surface antigens of B. cereus with molecular masses of 28.5, 26.5 and 20 kDa and the mixture thereof; and
(b) detecting the existence of B. cereus if the antibody-antigen binding reaction is positive.
Another objective of this invention is to provide a kit for rapid identification of B. cereus, which comprises a solution of antibody or antisera against the cell surface antigens of B. cereus, and the agents and apparatus required for detection of binding reaction between the said antibody or antisera and the bacteria antigen in a test sample; wherein the antigen is selected by at least one from the group consisting of: surface antigen of B. cereus with molecular masses of 28.5, 26.5 and 20 kDa and the mixture thereof.